1. Field of the Invention
The present invention relates to a method of updating registered information for updating and re-registering the registered information on an updated digital map. The registered information includes information about an institution, piping, an electric wire, and so on. More particularly, the method is capable of mechanically carrying out a registration processing without assistance.
2. Description of the Related Art
Conventionally, gas companies and electric power companies have introduced a geographic information system (GIS) for managing by registering positions of gas pipes and power lines which are provided, and relay and maintenance institutions, on a digital map. Therefore, they have attempt to utilize the digital map.
In the case in which a basic drawing of digital map data is updated, data (coordinate point) on position information registered in an old digital map cannot be simply copied onto a new digital map. Then, it is necessary to re-register the data with confirmation of the relationship between a road in the old map and that in the new map.
The data on the digital map include an error caused by being reduced scale. Therefore, the confirmation work is required. For example, a map of 1/25000 includes an error of approximately 50 m depending on a place. Such an error has gradually been corrected with the advancement of a measuring technique. For this reason, in many cases in which the digital map is updated, the position of a road on the old map is moved by several tens meters on the new map.
FIGS. 8(a), (b), and (c) typically show the above state. FIG. 8(a) shows a positional relationship between data on a road in an old map and a registered institution A. A white circle on the road indicates a position of a node on digital map data. The node is a point on the road and is set corresponding to an intersection, the entry and exit of a tunnel, the entry and exit of a bridge, and the boundary of an administrative district. Moreover, a black circle on the road indicates an interpolation point and is set to reproduce the shape of the road (link) between the nodes.
When the basic drawing of the digital map data is updated and the position of the road is changed as shown in a dotted line of FIG. 8(b), the institution A positioned on the left side of a road in an old map is moved to the right side of the road if data on the position are simply copied onto a new map. As shown in FIG. 8(c), thus, it is necessary to carry out a processing of a re-registering, in a correct position on the road in the new map, registered information which has the positional relationship with the road changed by the update of the digital map data.
A work for reviewing registered information with the update of the digital map has conventionally been carried out manually and a large number of workers have performed the work by taking a long time.
In order to solve such a conventional problem, it is an object of the invention to provide a method of updating registered information in a digital map which can be processed mechanically.
The invention provides a method of updating registered information on an old map to be re-registered on a new map when the old map is updated to the new map, including the steps of acquiring coordinate series data representing a shape of a road around a registration point on the old map from a data base of the old map, thereby obtaining a positional relationship between a reference point included in the shape of the road and the registration point, and carrying out shape matching on the new map by using the coordinate series data, obtaining a shape of a road on the new map corresponding to the shape of the road, acquiring a reference point on the new map corresponding to the reference point from the shape of the road thus obtained, and specifying the registration point on the new map based on a positional relationship with the reference point on the new map.
Therefore, the registration point on the new map can be specified mechanically even if a person does not decide the same registration point.